Splitter Card with Integral Test Access

ABSTRACT

A splitter card having integral test access devices. The splitter card allows test access to be readily provided at any location where splitter cards are typically mounted (e.g., a splitter chassis).

FIELD OF THE INVENTION

The present invention relates generally to telecommunications equipment.More particularly, the present invention relates to telecommunicationsequipment used in twisted pair telephone carrier systems.

BACKGROUND OF THE INVENTION

Telecommunications systems for transmitting voice and data to and fromsubscribers (i.e., residences and businesses) are known. An exemplarytelecommunications system 10 is schematically shown in FIG. 1. Thesystem 10 includes a Main Distribution Frame 12 (MDF) for connectingdigital subscriber lines 13 (DSLs) to internal lines 14 within atelephone server's central office 15. The central office 15 frequentlyincludes a DSLAM 18 (Digital Subscriber Line Access Multiplexer) and avoice switch 19. The DSLAM 18 transmits data to and receives data from acommunications network/backbone 21. The voice switch 19 transmits voicesignals to and receives voice signals from a communicationsnetwork/backbone 23. The networks 21 and 23 can be dedicated lines thatare part of the same network. POTS splitter devices 16 (i.e., Plain OldTelephone Service splitter devices) are used at the central office 15 tocombine data signals from the DSLAM 18 with voice signals from the voiceswitch 19. By combining the signals, the signals can be simultaneouslyrouted to a subscriber 25 through a single DSL 13. Signals transmittedfrom subscribers 25 to the central office 15 are also routed through thePOTS splitter devices 16. At the POTS splitter devices 16, the signalsare split and directed to the DSLAM 18 and the voice switch 19.Typically, the splitter devices 16 include low pass filters for removingthe data content from any signals transmitted from the splitter devices16 to the voice switch 19. Since DSLAMs 18 frequently include high passfilters for removing the voice band, the splitter devices 16 usually donot include filters for filtering the voice content from the signalstransmitted to the DSLAM 18.

For most telecommunications systems, it is desirable to maximize thesplitter densities. To maximize splitter densities, multiple splitterscan be mounted on a printed circuit board to form a splitter card. Tofurther maximize splitter densities, multiple splitter cards can bemounted within the same chassis.

It is desirable to be able to easily test the communication lines of atelecommunications system to identify errors and to determine whetherexisting lines are ADSL compatible (i.e., a process known as loopqualification). What is needed is a test access device that providesready test access to communication lines.

SUMMARY OF THE INVENTION

One aspect of an embodiment of the present invention relates to asplitter card having integral test access devices. The splitter cardallows test access to be readily provided at any location where splittercards are typically mounted (e.g., a splitter chassis).

A variety of other aspects of the invention are set forth in part in thedescription that follows, and in part will be apparent from thedescription, or may be learned by practicing the invention. The aspectsof the invention relate to individual features as well as combinationsof features. It is to be understood that both the foregoing generaldescription and the following detailed description are exemplary andexplanatory only and are not restrictive of the invention as claimed.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram of an exemplary telecommunications system;

FIG. 2 is a perspective view of a splitter unit including a chassis thatis shown fully loaded with splitter cards;

FIG. 3 is an exploded view of the splitter unit of FIG. 2;

FIG. 4A is a plan view of one of the splitter cards of the splitter unitof FIG. 2;

FIG. 4B is a front perspective view of the splitter card of FIG. 4A;

FIG. 4C is a front view of the splitter card of FIG. 4A;

FIG. 5 is a schematic diagram of one circuit of the splitter unit FIG. 2showing how a splitter card interfaces with the splitter chassis;

FIG. 6 is a schematic diagram of a splitter card with test access inaccordance with one aspect of the present invention;

FIG. 7 shows another splitter card with test access in accordance withthe principles of the present invention; and

FIG. 8 illustrates a further splitter card with test access inaccordance with the principles of the present invention.

While the invention is amenable to various modifications and alternativeforms, specifics thereof have been shown by way of example in thedrawings and will be described in detail below. It is to be understood,however, that the intention is not to limit the invention to theparticular embodiments described. On the contrary, the invention isintended to cover all modifications, equivalents, and alternativesfalling within the scope of the invention as defined by the appendedclaims.

DETAILED DESCRIPTION

In the following detailed description, references are made to theaccompanying drawings that depict various embodiments in which theinvention may be practiced. It is to be understood that otherembodiments may be utilized, and structural and functional changes maybe made without departing from the scope of the present invention.

It will be appreciated that the various aspects of the present inventionare applicable to a variety of telecommunications service optionsincluding, among other things, ADSL (Asymmetric Digital SubscriberLine), IDSL (Integrated Services Digital Network DSL), SDSL (SymmetricDSL) and VDSL (very high speed DSL) services.

I. Exemplary Splitter Unit

FIGS. 2 and 3 illustrate a splitter unit 50 that is an example of thetype used at a telephone server's central office. The splitter unit 50includes a chassis 52 for housing a plurality of splitter cards 55. Thechassis 52 includes mounting flanges 106 for allowing the splitter unit50 to be fastened (e.g., by screws or bolts) to a conventional rack orcabinet.

As best shown in FIG. 3, the splitter unit 50 includes LINE connectors76, POTS connectors 78 and DATA connectors 80. The LINE connectors 76can be used to provide interface locations for allowing the splitterunit 50 to interface with outside lines such as digital subscriber lines13 (see FIG. 1). The POTS connectors 78 can be used to provide interfacelocations for allowing the splitter unit 50 to interface with a voiceswitch such as voice switch 19 (see FIG. 1). The DATA connectors 80 canbe used to provide interface locations for allowing the splitter unit 50to interface with a DSLAM such as DSLAM 18 (see FIG. 1). The splitterunit 50 further includes first card edge connectors 96 and second cardedge connectors 97 for providing an electrical interface between thesplitter unit 50 and the splitter cards 55. A backplane board 68 (shownin FIG. 3) electrically connects the POTS and LINE connectors 76 and 78to the card edge connector 96, and also electrically connects the DATAconnectors to the card edge connector 97. In a non-limiting embodiment,the connectors 76, 78 and 80 can be RJ-21 connectors for use inproviding connections with corresponding connectors provided on cablessuch as 25-pair twisted pair cables.

Referring now to FIGS. 4A-4C, one of the splitter cards 55 is shown inisolation from the splitter chassis 52. The depicted splitter card 55includes a plurality of splitters 82 (e.g., 24 splitters) mounted on acircuit board 84. The card 55 also includes a front face plate 86mounted to a front edge of the circuit board 84. Retaining latches 88are located at left and right edges of the face plate 86 for retainingthe splitter card 55 within the chassis 52. The card 55 also preferablyincludes first and second card edge extensions 89 and 91 (i.e., cardedge connectors) located adjacent a rear edge of the circuit board 84.Preferably, electrical contacts/pads 93 are located on both the top andbottom sides of the card edge extensions 89 and 91. Tracings (not shown)on the circuit board 84 electrically connect the pads 93 to thesplitters 82. When the card 55 is fully inserted in the chassis 52, theextensions 89 and 91 are respectively received in the first and secondcard edge connectors 96 and 97 to provide an electrical interfacebetween the splitter card 55 and the splitter chassis 52.

The splitters 82 of the splitter unit 50 can have a number of differentconfigurations. For example, the splitters 82 can include conventionalPOTS splitter circuits. A conventional POTS splitter circuit functionsto split a signal (e.g., a signal from a DSL) into two signals. One ofthe split signals is typically passed through one or more low passfilters capable of passing the relatively lower frequency voice contentof the signal (e.g., less than about 4 kilohertz) and rejecting thesignal content above the voice band (e.g., 30 kilohertz and above). This“voice-only” signal can then be transmitted from the splitter 82 to avoice switch such as voice switch 19. The other split signal can betransmitted from the splitter 82 to a DSLAM such as DSLAM 18. For suchan embodiment, it is assumed that the DSLAM or other digitalmulti-plexer that ultimately receives the composite signal will provideany required high-pass filter elements to remove the relatively lowfrequency voice signal content of the composite signal. In otherembodiments, high pass filtration can be done at the splitter 82. Itwill further be appreciated that ISDN (Integrated Services DigitalNetwork) filter circuits could also be used. Exemplarysplitters/combiners incorporating low pass filters are sold byVacuumschmelze GMBH of Germany.

It will be appreciated that signals are transmitted bi-directionallythrough the splitters 82. Signals transmitted from DSLAMs and voiceswitches to the splitters 82 are combined at the splitters 82 such thatthe signals can be simultaneously routed to a subscriber 25 through asingle DSL 13.

FIG. 5 schematically shows the interface between the splitter chassis 52and one of the splitter cards 55. In FIG. 5, only one twisted paircircuit/channel is shown. It will be appreciated that similarcircuits/channels are preferably provided for each of the remainingsplitters.

In FIG. 5, the splitter card 55 is shown connected with card edgeconnectors 96 and 97. With the interface between the splitter card 55and the card edge connectors 96 and 97, LINE signals (e.g., signals froma DSL) inputted through LINE connector 76 are directed through tracings128 of backplane board 68 to card edge connector 96. From card edgeconnector 96, the signal is conveyed to splitter 82 of splitter card 55.At splitter 82, the LINE signal is split into separate VOICE and DATAsignals. The VOICE signal is directed back through card edge connector96 to tracings 126 of the backplane board 68. Tracings 126 carry theVOICE signal to POTS connector 78 where the VOICE signal is output fromthe splitter unit 50 to a component such as voice switch 19. The DATAsignal is directed from splitter 82 to card edge connector 97. From cardedge connector 97, the DATA signal is carried by tracings 130 ofbackplane board 68 to DATA connector 80. At DATA connector 80, the DATAsignal is output from the splitter unit 50 to a component such as DSLAM18. Signals traveling in the reverse direction through the splitter card55 (i.e., signals input through the POTS and DATA connectors 78 and 80from the voice switch and DSLAM) are combined at the splitters 55 andoutput through the LINE connector 76 (e.g., to a DSL).

II. Splitter Card With Integral Test Access

FIG. 6 schematically shows a splitter card 120 constructed in accordancewith the principles of the present invention. The splitter card 120includes a circuit board 84′ on which a plurality of POTS splitters 82′are mounted (only one splitter is shown in FIG. 6). The splitter card120 also includes test access devices 122 (only one shown in FIG. 6)that provide test access to signals being transmitted through thesplitter card 120. The test access devices are preferably integral withthe splitter card 120 (i.e., the circuit board 84′, the splitters 82′and the test access devices 122 form a single unit). While the preferredembodiment includes POTS splitters, ISDN splitters could also be used.

The circuit board 84′ preferably has a similar configuration to thecircuit board 84 previously described. For example, the circuit board84′ includes card edge connectors in the form of first and second cardedge extensions 89′ and 91′. Preferably, electrical contacts/pads 93′are located on both the top and bottom sides of the card edge extensions89′ and 91′. As will be described in greater detail later in thespecification, circuitry (i.e., electrically conductive components suchas tracings) electrically connects the pads 93′ to the splitters 82′ andthe test access devices 122. The circuit board 84′ is sized to fitwithin the splitter chassis 52 of FIGS. 2 and 3. By inserting thesplitter card 120 within the chassis 52, the extensions 89′ and 91′ arerespectively received in the first and second card edge connectors 96and 97 of the chassis 52. As so inserted, the pads 93′ engage contactsof the card edge connectors 96 and 97 to provide an electrical interfacebetween the splitter card 120 and the splitter chassis 52.

For clarity, only one splitter 82′ and one test access device 122 areshown mounted on the circuit board 84′. However, it will be appreciatedthat a plurality of POTS splitters 82′ and a plurality of test accessdevices 122 are preferably provided. For example, when used incombination with the chassis 52, the circuit board 84′ is preferablyequipped with 24 POTS splitters 82′ and 24 test access devices 122. Eachof the test access devices 122 preferably has three ports for providingtest access to the LINE signal, the POTS signal and the DATA signal ofeach circuit or channel of the splitter card 120. It will be appreciatedthat the number of splitters 82′ and the number of test access devices122 can be varied to be compatible with a particular splitter chassis.

The POTS splitters 82′ of the splitter card 120 preferably have the sameconfiguration as the POTS splitters 82 previously described with respectto the splitter card 55. As shown in FIG. 6, the depicted splitter 82′includes a low pass filter 83 used to remove the data frequency band ofa signal. In use of the splitter card 120, a LINE signal transmitted tothe splitter card 120 from a DSL (see DSL 13 of FIG. 1) is split withinthe POTS splitter 82′. One part of the split signal is passed throughthe low pass filter then output from the splitter card 120 as a POTSsignal. The other part of the LINE signal is not filtered and thereforeretains the content of the signal corresponding to the data frequencyband. This part of the signal is output from the splitter card 120 as aDATA signal. Frequently, the low frequency voice content of the DATAsignal can be filtered at a downstream location such as at a DSLAM. DATAand POTS signals transmitted to the splitter card 120 from componentssuch as a DSLAM or a voice switch (see DSLAM 18 and voice switch 19 ofFIG. 1) are combined at the splitter 82′ and output from the splittercard 120 as a LINE signal.

The test access devices 122 of the splitter card 120 can includenormally-through bantam jacks. As shown in FIG. 6, the depicted bantamjack defines three ports which include a LINE port 124, a POTS port 126and a DATA port 128. Each of the ports 124-128 is sized for receiving atip and ring plug, and each includes a corresponding tip spring 130 andring spring 132. The tip and ring springs 130 and 132 normally engagecorresponding normal contacts 134. Thus, when no plug is inserted in agiven port 124-128, the tip and ring springs 130 and 132 engage theircorresponding normal contacts 134 such that the circuits are closed.However, when a tip and ring plug is inserted within one of the ports124-128, the plug engages the tip and ring springs 130 and 132corresponding to the port causing the tip and ring springs 130 and 132to be biased away from their corresponding normal contacts 134. In thismanner, any signal being conveyed between the tip and ring springs 130,132 and the normal contacts 134 is interrupted and routed through theplug inserted within the corresponding port. With the plug inserted inthe port, the tip spring 130 of the port engages the tip of the plug andthe ring spring 132 of the port engages the ring of the plug. As isconventionally known in the art, the bantam jacks also preferablyinclude sleeve grounds (not shown).

In use of the splitter card 120, the splitter card 120 is insertedwithin the chassis 52 of the splitter unit 50. As so inserted, LINEsignals input to the splitter unit through one of the LINE connectors 76enters the splitter card 120 through the first card edge extension 89′.From the first card edge extension 89′, the LINE signal travels throughtracings 136 _(T) and 136 _(R) to the tip and ring springs 130, 132 ofthe LINE port 124. In the absence of a plug in the LINE port 124, thesignal travels from the tip and ring springs 130, 132 to theircorresponding normal contacts 134. From the normal contacts 134,tracings 138 _(T) and 138 _(R) convey the signal to POTS splitter 82′.At the POTS splitter 82′, the signal is split into a POTS signal and aDATA signal. The POTS signal passes through the low pass filter 83 ofthe splitter 82′ and is carried by tracings 140 _(T) and 140 _(R)through the tip and ring springs 130, 132 of the POTS port 126. In theabsence of a plug in the POTS port 126, the POTS signal travels throughthe tip and ring springs 130 and 132 to the corresponding normalcontacts 134. From the normal contacts 134 tracings 142 _(T) and 142_(R) convey the POTS signal back to the first card edge extension 89′.From the first card edge connection 89′, the POTS signal is output fromthe splitter unit 50 through one of the POTS connectors 78.

The DATA signal by-passes the low pass filter 83 of the splitter 82′ andis carried from the POTS splitter 82′ to the tip and ring springs of theDATA port 128 by tracings 144 _(T) and 144 _(R) In the absence of a plugin the DATA port 128, the DATA signal is carried from the tip and ringsprings 130 and 132 of the DATA port 128 to the corresponding normalcontacts 134. From the normal contacts 134 of the DATA port 128, thesignal is carried to the second card edge extension 92′ by tracings 146_(R) and 146 _(T). The DATA signal is then preferably output from thesplitter unit 50 through one of the DATA connectors 80.

The above paragraphs describe the path of signals traveling from theLINE connectors 76 to the POTS and DATA connectors 78 and 80. It will beappreciated that signals traveling from the POTS and DATA connectors 78and 80 to the LINE connectors 76 travel along the same path, but in anopposite direction.

It will also be appreciated that the splitter card 120 of FIG. 6 is butone example of the present invention. In other embodiments, theconfiguration of the structure for providing an electrical interfacewith the chassis 50 can be modified. For example, a single card edgeextension could be used. Alternatively, female connectors could bemounted on the circuit board 84 for providing an interface with achassis. Moreover, the size of the circuit board 184 can be varied tocorrespond to the size of a chassis in which the card is intended to beinserted. Further, the test access devices may be configured to providetest access to only the LINE signals, only the DATA signals or only thePOTS signals (i.e., fewer than 3 access ports can be provided perchannel if desired).

FIG. 7 shows another embodiment of a splitter card 220 constructed inaccordance with the principles of the present invention. The splittercard 220 includes a main board 284 having POTS splitters 282 mountedthereon. The POTS splitters 282 are preferably mechanically coupled tothe main board 284. The splitter card 220 also includes two daughterboards 295 that are mechanically coupled to the main board 284. Testaccess devices 222 are mechanically coupled to the daughter boards 295and the main board 284. Electrical connectors 297 provide electricalinterfaces between the daughter boards 295 and the main board 284. Posts299 can be used to stabilize the mechanical coupling between thedaughter boards 295 and the main board 284.

As shown in FIG. 7, the test access devices 222 comprise bantam jackshaving electrical contact pins 298 corresponding to each of the tipsprings, ring springs and normal contacts located within the bantamjacks. The posts 298 are press fit within plated through holes definedby the main board 284 and the daughter boards 295. In this manner, theposts 298 provide both an electrical and mechanical coupling between thetest access devices 122 and the circuit boards 284 and 295.

In the embodiment of FIG. 7, the splitter card 224 can include 24different POTS splitters 282. The daughter boards 295 have been added toprovide additional mounting space for mounting bantam jackscorresponding to each of the splitters 282. It will be appreciated thatsignals can be routed between the bantam jacks and the splitters in thesame manner shown with respect to the embodiment of FIG. 6. Electricalconnectors 297 provide a means for transferring signals between the mainboard 284 and the daughter boards 295.

As used herein, the phrase “mechanically coupled” includes situationswhere one component is connected directly to another component (e.g., byfasteners such as rivets, screws or pins or other means such asadhesive) and also includes situations in which one component isconnected to another component by one or more intermediate members.

The test device 122 of FIG. 6 can be referred to as an “intrusive” testdevice because when a plug is inserted within one of the ports 124-128,the corresponding signal being routed through the splitter card 120 isinterrupted and routed through the plug. FIG. 8 shows a splitter card120′ having the same configuration as the splitter card 120 of FIG. 6except the intrusive test access device 122 has been replaced with anon-intrusive test access device 122′. The non-intrusive test accessdevice 122′ allows the splitter card 120′ to continuously function as asplitter even during testing procedures. The test access device 122′includes a LINE port 124′, a POTS port 126′ and a DATA port 128′. Thetest access device 122′ is configured such that no signals areinterrupted during testing. For example, when a plug is inserted withinthe LINE port 124′, a continuous electrical connection is maintainedbetween tracings 136 _(R), 136 _(T) and tracings 138 _(R), 138 _(T)Similarly, when a plug is inserted within the POTS port 126′, acontinuous electrical connection is maintained between tracings 140_(R), 140 _(T) and tracings 142 _(R), 142 _(T). Moreover, when a plug isinserted within the DATA port 128′, uninterrupted electrical connectionsare maintained between tracings 144 _(R), 144 _(T) and tracings 146_(R), 146 _(T). When a plug is inserted within one of the ports124′-128′, rather than directing the entire signal through the plug,only a small portion of the signal is directed therethrough. Resistors121 prevent the entire signal from being routed through the plug. In apreferred embodiment, the resistors have resistance in the range of40-70 kilohms.

While the test access devices depicted above have primarily beendescribed as bantam jacks for use with tip and ring plugs, it will beappreciated that any type of structure or connector for gaining accessto signals routed through the splitter card could be used.

The above specification and examples provide a complete description ofthe manufacture and use of the invention. Since many embodiments of theinvention can be made without departing from the spirit and scope of theinvention, the invention resides in the claims hereinafter appended.

1. A telecommunications device comprising: at least one circuit board; aplurality of POTS splitters mounted to the circuit board; and aplurality of test access devices mechanically coupled to the circuitboard. 2-23. (canceled)